Tripping mechanism for power-shovels.



J. H. FREEL.

TRIPPING MECHANISM FOR POWER SHOVELS. APPLICATION FILED APR.16, 190s. RENEWED JAN. 21, 1909.

' 93 1 ,747 Patented Aug. 24,;1909.

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.J'OHN H. FREEL, DE LAS CASCADAS, FANAMA.

TRIPPING IMCEGHANISM FOR POWER-SHOVELS. 7

Specification of Letters Patent.

Patented Aug. 24, 1909.

- Applicatimi filed April 16, 1908, Serial No. 427,357. Renewed January 21, 1909. Serial No. 473,469.

To all whom it may concern:

Be it known that I, JOHN H. F REEL, a citi-' ments in devices relating to power excavators, and'particularly to steam shovels.- In the use of apparatus of this class it has been found exceedingly difiicult to provide ameans for operating the tripping mechanism for the shovel with convenience, facility, and precision. The shovel being so large ordinarily. and the contents thereof being so massive, the door locking device and the means for unlocking the same are required to be exceedingly strong, and for the reason that the apparatus is subjected to the greatest amount of rough usage, it has been found very difficult to provide in actual practice a tripping mechanisl'n which is easy to operate.

For a full understanding of the present invention, including its mode of operation and advantages, reference is to be had to the following description and the accompanying drawings, in wl1i ch Figure 1 is a general View in elevation showing a fragment of a power shovel boom, a dipper mounted thereon, and showing the present invention in its relation to said' parts; Fig. 2 is avertical sectional viewof the invention on an enlarged scale; Fig. 3 is a transverse sectional detail taken on the line 33 of Fig. 2, and Fig. & is a detail perspective of a slight modificationof the invention.

Throughout the following description and on the several figures of the drawings similar parts are referred to by like reference characters.

The improvements comprising the present invent-ion are adapted for a considerable range of use, but as a preferred embodiment of this application I have herein illustrated, in a conventional way, a boom' 10 which will be understood to be a part of a power excavating apparatus. This boom is operated ordinarily by the engineer on the main part of the machine in order to elevate the same or swing it laterally. The dipper 11, connected to the dipper arm 12, is-operated ordinarily by a craneman located usually upon tion with gearing mounted on the boom and driven by an independent engine directly under control of the craneman. The arm 12 is shown as being provided with teeth.13 in mesh with a pinion 14 mounted on a shaft 15, :driven by one or more bull-wheels 1G driven by as many pinions 17 on the engine shaft.

Thus far described the apparatus is conventional.

The dipper bottom 18 is hinged at its upper edge at 19 to the dipper. Ordinarily the bottom 18 closes automatically by gravity and is locked closed by a latch 20 which .cooperates with a lip 21, as a stationary part of the dipper. loaded and elevated over the car or dump upon which its contents are to be discharged, the latch 20 is usually opened eitherby hand or by having connected thereto a connection in the nature of a cable or rope 22 leading to some distant point, such as to the engineer on the machine,to the craneman, or in some instances the free end of such cable is snubbed about a post or some other fixed point which will serve to draw the latch out of engagement with the lip in the event that the dipper reaches a certain elevation or distance from the machine. In all such means ordinarily employed for operating the locking mechanism there has been experienced a great deal ofloss of time and annoyance due among other things to the fact that the cable 22 is liable either to have too much slack or else if the end of the cable is fixed there is danger of its being drawn upon too soon, and furthermore it has been found difIicult-to provide means which will readily permit the dumping of the dipper in any one of a number of different positions, it being desirable to dump on different parts of a flat car for instance.

Referring now particularly to Fig. 2', I

tension of theboom 10. The shaft 23 isnormally stationary, and is secured in such position by a suitable locking device such as a set screw 25. Mounted loosely upon the.

shaft 23 is a drum 26 housed within which is a spiralspring 27, one end of which is secured to the shaft and the other end is secured tothe drum. The drum furthermore is provided with a concave periphery 28 After the dipper has been end of the spring is passed and therein secured, the slot being enough longer than the width of the s ring to permit free movement of the drum ongitudinallyofthe shaft as may be desired. The purpose of the spring is to" cause they drum 26 to automatically wind up all looseness or slack in the'cable 22.v

To'this end in 'assembling'the device, the dipper may be elevated to the point nearest the drum or bull-wheel and the operator will then wind up the spring justto the proper tension, as .by application of a wrench to the squared end 23" of the shaft, and then lock the shaft in place as before stated. Upon outward or downward movement of the dipper thereafter the cable 22 will turn the drum, paying out therefrom, and winding up the spring 27. It will be understood of course thatthe spring 27 will be of any desired length to permit of operation of the dipper. It will now be understood that as the dipper is manipulated in either direction the tension of the spring will be sufficient to automatically cause the cable 22 to wind upon the drum 26.

Thus far described it will be appreciated that the cable and drum intheir movements will follow the movements of the dipper. In order to trip the latch mechanism and dump the dipper, it will only benecessary therefore to either stop the rotation of the drum or cause it to rotate in the reverse direction to cause the cable to trip the latch mechanism while the dipper is moving outwardly,

such direction of movement of the dipper being theone in which it is ordinarily desirable to dump the same. As one of the several ways in which I may sto such rotation of the drum 26 and therea tercause it to rotate reversely- I may provide an suitable form of a clutch device, herein in icated as a friction clutch, one part 29 of which is secured to the drum and the other part 30 of which is secured to ormade an integral part of a pinion 31 mounted loosely upontlie aforesaid shaft 23, and in mesh with the bull-wheel 16. The pinion 31 and actuatingmember secured thereto may beheld in proper' position on the shaftby adjustable collars 32. By reference to Fig. 1 it will be noted that when the dipper is moving out wardly the bull-wheel Wlll cause a rotation of the pinion 31 in a direction opposite to the direction in which the drum 26 is rotated. If then the drum is moved longitudinally on-the shaft causing the members of the clutch to engage each other, the drum will be stopped, or if the friction is sufficiently great will be caused to rotatcin uni- .son with the pinion 31, such pinion being always in mesh with the bull-wheel. The result ther'efore'will be to either stop the rope 22 or draw it rearwardly, releasing the latch and permitting the contents of the dipper to dump. ,The drum 26. may be moved longitudinally of the above parts by means of a yoke 33 connected to a bell crank 34 pivoted to the support 24. The bell' crank 34 may be operated by a lever"35-within reach of the craneman. In-order to insure the ready disengagement ofthe clutch members 29 and 30 a spring 36 or its equivalent may be employed, herein indicated 'asbeing attached to the bell crank 34. r r

In the modification illustrated Fig. '4:

the same invention, in all essential features as that above described, is used. Instead, however, of providing means for stopping the rotation of the drum and then causing it to move in a reverse direction, I have shown frictional means in the form of a strap brake to stop the rotation of the drum. In this construction the-same arrangement of the shaft 23- and its mountings is employed, the spring within the drum is the same, and the operation of the spring and drum, excepting as just stated, is the same as in the other case. 'In this construction the strap brake 37 may be operated by any suitable lever, such as a foot lever 38, under the immediate control of the operator. the dipper is moving outwardly and as it nears the point at which it is to be dumped the operator will apply friction to the drum,

When

stopping the same, and thereby trip the I improvements comprislng my invention are by no means of. a delicate nature, and also that the spring is thoroughly-housed within the drum it is well protected. The inven tion therefore is of a simple nature and not likely to get out of order.

Having thus described the invention, what -1s claimed as new, is: i

1. The hereindescribed improvement in tripping mechanismfor power shovels com-- prising, in combination, a fixed support, a drum rotatable uponsaid support, a spiral ,spr'ing within the drum connected at one end to the support, coiled therearound, and fixed at the other end to the drum, a; cable secured to the periphery of the drum and wound thereupon inthe same direction in which the spiral sprin is coiled about the support, and means under the control of the I operator to check the rotation of the drum. 2. In combination, a boom, a dipper mounted thereon, means on said boom including a bull-wheel for operating said dipper, the dipper having a movable bottom, a latch to secure the bottom closed, a cable secured to the latch to trip the same, a stationary support on the boom, a drum rotatable upon said support and upon which said cable'is wound, a. coil spring within the drum one end of which is secured to the support and the other end to the drum, a

plnion. on said support and in mesh with said bull-wheel, and means to cause saicl' pinion' to control the movement of, the drum.

3. In combination, a boom, a dipper operated'thereupon, tripping means'for the dipper including a cable, a supp'orting'shaft mounted upon the boom, a drum rotatable upon the-said shaft and to which the cable is connected, means within the drum to cause the same to wind the cable thereupon, means under the controlof the operator for applying friction to the drum to control its movements, and means for adjusting said shaft and locking the same in its supports With respect to the saidmeans within the drum.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN H. FREEL. \Vitnesses OSCAR G. HOOSE, T. J Cmwso 

